Liquid mixtures of alkyl carbamates



LIQUID MIXTURES F ALKYL CARBAMATES Sidney Beinfest and Phillip Adams, Berkeley Heights,

and Joseph Halpern and Marvin Weiss, New Providence, N.J., assignors to Berkeley Chemical Corporafiion, Berkeley Heights, N.J., a corporation of New ersey N0 Drawing. Filed Mar. 10, 1960, Ser. No. 13,990 14 Claims. (Cl. 106-195) This invention relates to novel liquid mixtures. More particularly, it relates to novel compositions of liquid mixtures of alkyl carbamates, the mixtures being excellent solvent systems.

Alkyl carbamates are well known organic chemicals which are solids at room temperature.

It has now surprisingly been found that mixtures of alkyl carbamates which individually are solid at room temperature are capable of forming liquid mixtures at that temperature. This phenomenon is unpredictable in nature in that some combinations of alkyl carbamates form liquid mixtures and others do not. This is elaborated upon below.

For the purposes of this invention, the liquid mixtures connote mixtures which are liquid at room temperature, i.e. 25 C.

The alkyl carbamates that can be employed in the compositions of this invention conveniently have alkyl groups having from 1 to 18 carbon atoms andpreferably from 1 to 8 carbon atoms. The alkyl carbamates of this invention are thus binary mixtures, although ternary and quaternary and multicomponent ones also can be prepared. 1

The mixtures can be made up by admixing the solids and, if desired, grinding them together at room temperature. They can also be prepared by heating the components above their melting points and mixing the liquids. The mixture remains liquid at room temperature.

The liquid mixtures of this invention have great utility as novel solvent systems for'many solutes. Thus, they are extremely interesting and eflicacious solvents for gases such as S0 NH H 8, H01 and CHECH; aromatics such as benzene, toluene and styrene; chlorocarbons such as chloroform; esters such as ethyl and butyl acetate; organic acids such as acetic, oleic and caprylic; alcohols such as methanol, glycerol and cyclohexanol and ethers. They also dissolve inorganic solids such as ZnCl SnCl KMnO.,, Hgcl NH SCN, KI, KOCOCH etc. They are also fine solvents for lacquers, shellacs, nitrocellulose, carbowax, and various plastics such as acrylates. The solvent mixtures are particularly good as recrystallizing media for sugars such as sucrose. Particularly important solutions are those of nitrocellulose or sugar in liquid mixtures of ethyl and methyl carbamates.

The mixtures of this invention can also be employed as either inert diluents or process reactants themselves.

This invention and its advantages will be better understood by reference to the following examples.

EXAMPLE 1 Table I below lists binary systems, alkyl'carbamates that formed liquid mixtures of this invention, together with the composition necessary to give the requisite liquidity at room temperature.

The following pairs of solid alkyl carbamates do not give liquid mixtures at room temperature:

Table II n-Amyl carbamate Methyl earbamate. n-Propyl carbamate Isobgtyl carbamate.

Ethyl carbamate. o. n Propyl carbama Isopropyl carbamate. n-Butyl earbamate Isobutyl carbamate. n-Propyl carbamate... n-Butyl carbamate. Ethyl earbamate n-Propyl carbamate. Methyl carbamate Isopropyl carbamete.

2-Ethyl butyl carbamate. n-Butyl earbamat Do. Ethyl carbamate. Isopropyl earbamate.

o 2-Ethyl butyl earbamate. Isopropyl carbarnate Isobutyl carbamate.

Do n-Amyl earbamate.

This demonstrates the unpredictable nature of this invention.

EXAMPLE III Various solutes were dissolved in liquid mixtures of ethyl and methyl carbamates. Typical of these solutes were nitrocellulose, 2-methyl-2-n-propyl propane 1,3 diol, sucrose, salicylic acid, quinine, rutin, cholesterol and thiourea.

As stated previously, multi-component carbamate systems can be prepared higher than binaries and also are useful as solvents. Thus, ternary liquid systems can be prepared where any of the possible binaries are solids at room temperature. Similar higher multi-component systems can be prepared. An example of the former is n-propyl carbamate, 29%, ethyl carbamate, 48%, and n-butyl carbamate, 23%. An example of a quaternary system is n-propyl carbamate, 19%, n-butyl carbamate, 25%, ethyl carbamate, 31%, and n-amyl carbamate, 25%.

The advantages of this invention will be apparent to those skilled in the art. Novel liquid mixture solvents are provided which are both economical and promising for future work.

It is to be understood that this invention is not limited to the specific examples, which have been ofiered merely as illustrations, and that modifications can be made without departing from the spirit thereof.

What is claimed is:

1. As a novel composition of matter a liquid mixture of alkyl ca'rbamates, said mixture being liquid at room temperature, the individual carbamates normally being solid at that temperature.

2. The composition of claim 1 in which the carbamates are a binary system.

3. The composition of claim Zin which the mixture of alkyl carbamates comprises ethyl and methyl carbamates, the ethyl carbamate making up from about 40 to about 65% of the carbamate mixture.

4. The composition of claim 2 in which the mixture of alkyl carbamates comprises n-butyl and ethyl carbamates, the n-butyl carbamate making up from about 38 to about 58% of the carbamate mixture.

5. The composition of claim 2 in which the mixture of alkyl carbamates comprises methyl and n-propyl carbamates, the methyl carbamate making up from about 43 to about 58% of the carbamate mixture.

6. The composition of claim 2 in which the mixture of alkyl carbamates comprises methyl and n-butyl carbamates, the methyl carbamate making up from about 40 to about 160% of the carbamate mixture.

7. As a novel composition of matter, a solvent system of a liquid mixture of alkyl carbamates, said mixture being liquid at room temperature, the individual carbamates being solid at that temperature, said system containing a solute in solution.

8. The composition of claim 7 in which the carbamates are a binary system.

9. The composition of claim 8 in which the carbamates are ethyl and methyl carbamates, the ethyl carbamate making up from 40 to about 6 5% of the carbamate mixture.

10. The composition of claim 9 in which the solute is sucrose.

11. The composition of claim 9 in which the solute is rutin.

12. The composition of claim 9 in which the solute is 2-methyl-2-n-propyl propane 1,3 diol.

13. The composition of claim 9 in which the solute is nitrocellulose.

14. The composition of claim 9 in which the solute is an aromatic hydrocarbon.

What You Can Use, Oil, Paint and Drug Reporter (July 31, 1939, issue, page 52; Aug. 7, 1939, issue, page 71; and Aug. 14, 1939, issue, page 34). 

1. AS A NOVEL COMPOSITION OF MATTER A LIQUID MIXTURE OF ALKYL CARBAMATES, SAID MIXTURE BEING LIQUID AT ROOM TEMPERATURE, THE INDIVIDUAL CARBAMATES NORMALLY BEING SOLID AT THAT TEMPERATURE. 